1. Field of the Invention
This invention pertains to a method of manufacturing a printed wiring board, and in particular, relates to a method of manufacturing a printed wiring board that can be used for a package substrate for mounting an integrated circuit (IC) chip.
2. Discussion of the Background
In a conventional method, solder bumps are used for an electrical connection between a package substrate and an IC chip. Solder bumps are conventionally formed with the following steps.
(1) A step of printing flux on connection pads formed in a package substrate.
(2) A step of loading solder balls on the connection pads with flux printed thereon.
(3) A step of forming solder bumps out of solder balls by reflow.
An IC chip is placed on solder bumps after the solder bumps are formed on a package substrate and the solder bumps and the pads (terminals) on the IC chip are connected by reflow such that the IC chip is mounted on the package substrate. For the above-described step of loading solder balls on connection pads, a printing technology using concurrently a ball arrangement mask and a squeegee is illustrated in Japanese Patent Document Laid-open patent No. 2001-267731, the entire content of which is incorporated herein by reference.